The header image in the below Timeline exhibit of Ruth Bader Ginsburg works really well because her face is located in the middle-third of the photo. The middle- third stays centered no matter what device your audience uses to view your exhibit.

However, in the below example you can see in the left image that RBG's face is now located in the top third of this alternative photo. If we use that photo as our header image in the same Timeline exhibit shown on the right, the middle third stays centered, but the top-third can fall outside of the viewport on certain devices. Make sure the most important part of your header image falls in the middle third.

When selecting header images for your individual collections in the David, LFLB or Digital Collections templates, use the same middle third rule as shown in the below example.

The header image used for the below Events collection in this exhibit looks great because the wedding couple is located in the middle-third of the photo. The couple will stay centered no matter what device or screen size your audience uses to view your exhibit.

However, if we use the alternate photo of the wedding couple on the left as the key image for the same Events collection, the focal point can fall outside of the viewport frame on certain devices.